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<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
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<body>
    
</body>
<script>
    //创建函数，生成当前时间的字符串，
    //2021~10~19 10；17；20
    //作为 函数的返回值返回
    function  identify(num){
        return num <10?"0"+""+""+num:num
    }
    function  sj(){
    var  date1 = new Date();
    var  year = date1.getFullYear();
    var month = date1.getMonth();
    month =month+1;
    var day = date1.getDate();

    var hour = date1.getHours();
    var minute =date1.getMinutes();
    var sec = date1.getSeconds();
    alert(year+"~"+month+"~"+day+" "+hour+":"+minute+":"+sec);
    month =identify(month);
    day = identify(day);
    hour = identify(hour);
    minute = identify(minute);
    sec = identify(sec);
    var result = year +"-"+month+"-"+day+" "+hour+":"+minute+":"+sec;
    return result;
    }
    document.write(sj());
   document.write((new Date).toLocaleString());
    </script>
</html>